To qualify for copyright protection, a work must be "fixed in a tangible medium of expression." This means that the work must exist in some physical form for at least some period of time, no matter how brief. Virtually any form of expression will qualify as a tangible medium, including a computer's random access memory (RAM), the recording media that capture all radio and television broadcasts, and the scribbled notes on the back of an envelope that contain the basis for an impromptu speech.

In addition, the work must be original -- that is, independently created by the author. It doesn't matter if an author's creation is similar to existing works, or even if it is arguably lacking in quality, ingenuity or aesthetic merit. So long as the author toils without copying from someone else, the results are protected by copyright.

Finally, to receive copyright protection, a work must be the result of at least some creative effort on the part of its author. There is no hard and fast rule as to how much creativity is enough. As one example, a work must be more creative than a telephone book's white pages, which involve a straightforward alphabetical listing of telephone numbers rather than a creative selection of listings.

Does copyright protect an author's creative ideas?

No. Copyright shelters only fixed, original and creative expression, not the ideas or facts upon which the expression is based. For example, copyright may protect a particular song, novel or computer game about a romance in space, but it cannot protect the underlying idea of having a love affair among the stars. Allowing authors to monopolize their ideas would thwart the underlying purpose of copyright law, which is to encourage people to create new work.

For similar reasons, copyright does not protect facts -- whether scientific, historical, biographical or news of the day. Any facts that an author discovers in the course of research are in the public domain, free to all. For instance, anyone is free to use information included in a book about how the brain works, an article about the life and times of Neanderthals or a TV documentary about the childhood of President Clinton -- provided that that they express the information in their own words.

Facts are not protected even if the author spends considerable time and effort discovering things that were previously unknown. For example, the author of the book on Neanderthals takes ten years to gather all the necessary materials and information for her work. At great expense, she travels to hundreds of museums and excavations around the world. But after the book is published, any reader is free to use the results of this ten year research project to write his or her own book on Neanderthals -- without paying the original author.

How long does a copyright last?

For works published after 1977, the copyright lasts for the life of the author plus 70 years. However, if the work is a work for hire (that is, the work is done in the course of employment or has been specifically commissioned) or is published anonymously or under a pseudonym, the copyright lasts between 95 and 120 years, depending on the date the work is published.

All works published in the United States before 1923 are in the public domain. Works published after 1922, but before 1978 are protected for 95 years from the date of publication. If the work was created, but not published, before 1978, the copyright lasts for the life of the author plus 70 years. However, even if the author died over 70 years ago, the copyright in an unpublished work lasts until December 31, 2002. And if such a work is published before December 31, 2002, the copyright will last until December 31, 2047.